1. Field of the Invention
Embodiments of the present invention generally relate to a method of forming a magnetic head without producing undesired residues.
2. Description of the Related Art
In the process of fabricating magnetic write heads, there are many steps that involve removing residues or thin films from metal surfaces, such as ruthenium. The residues can be carbon containing films that have been used as stopping layers during a reactive ion etching (RIE) process, as masking layers used in an ion milling process, as stopping layers used during a chemical mechanical polishing (CMP) process, or masking layers used for a wet etching process. Examples of the carbon containing films that may be used include polyimide, diamond like carbon (DLC) films or photoresist films.
There are two approaches to removing the carbon containing residues. The first approach involves wet chemical stripping using solvents such as NMP. The second approach is a dry plasma strip. Some films, such as amorphous carbon, polyimide or barrier antireflective coatings (BARCs), are more effectively removed using a plasma rather than a wet chemical stripping process. Plasma stripping is done in two ways. One way involves using a source plasma with no bias (for process tool simplicity and cost savings). Another way involves using a bias RIE process combined with the source power to remove the residues. While the source plasma etcher, commonly referred to as a plasma stripper, can be used to remove organic BARC, the amorphous carbon films can only be removed by the RIE etcher where both the source and bias powers are used.
In magnetic head fabrication, there are many instances where carbon films are deposited on a ruthenium surface and used as a stopping layer or a mask layer. When the RF bias is applied to the substrate to remove the carbon film from the ruthenium or other metal surface, non-volatile metal complexes are produced which tend to redeposit within the processing chamber, such as on process chamber walls, electrodes, chamber liner, and the gas distributer or showerhead. Since the plasma etch process is very sensitive to the environment, the redeposition of the metal complexes will cause a drift in the RIE process on any subsequently processed substrates within the same RIE chamber so that the profile control for any critical dimensions will be affected. Additionally, even for the non-critical applications such as residue removal, the etch rate may drop and the etch uniformity may degrade such that the residues are not removed effectively.
Therefore, there is a need in the art for a method to manufacture a magnetic write head without forming metal complexes that interfere with subsequent processing.